Various bug fixes
Three fixes:
- fix for blended material names that contain capital letters. All are converted to lowercase for consistency with material naming that comes from the mixing table.
- if a reactor is 2D, the z bounds for the volume calc are reset to 1 so that the reported volume corresponds to the 2D area. Tests have been added for this change.
- Formatting for the volume information in the summary is updated so that the volume numbers are more readable and long material/cell names don't misalign.
Edited by Kiesling, Kalin Rose